Railway traffic controlling apparatus with manual change-over from remote to local control



Nov. 4, 1947. T. w. HAYS 2,430,291

- RAILWAY TRAFFIC CONTROLLING APPARATUS WITH MANUAL CHANGEOVER FROM REMOTE TO LOCAL CONTROL I Filed Sept. 12, 1944 5 Sheets-Sheet 1 3 ZZA v2125' EIG I -U 212B ZZHD 2MB I F ZBHD a ZlP' HIP ZHAP 3 a IZZHDZZZAZI a 1G a IN VEN TOR H15 A TTORNE Y 2,430,291 RAILWAY TRAFFIC CONTROLLING APPARATUS WITH MANUAL Nov. 4, 1947. T. w. HAYS CHANGEOVER FHOMREMOTE TO LOCAL CONTROL Filed Sept. 12, 1944 5 Sheets-Shegt 2 ZM NH' I IN VEN TOR Thomar Z0. Hqym am HIS A TTORNE Y Nov. 4, 1947. T. w. HAYS 2,430,291

' RAILWAY TRAFFIC CONTROLLING APPARATUS WITH MANUAL CHANGEOVER FROM REMOTE TO LOCAL CONTROL Filed Sept. 12, 1944 3 Sheets-Sheet 3 si h- 5% l I I 1e f F y- INVENTOR H13 ATTORNEY Patented Nov. 4, 1947 UNITED STATES PATENT OFFICE RAILWAY TRAFFIC CQNTROLLING APPARA TUS WITH MANUAL CHANGE-OVER FROM REMOTE T LOCAL CONTROL Application September 12, 1944, Serial No. 553,689

.6 Claims. 1

My invention relates to railway traffic controlling apparatus, and more particularly to centralized traific control systems for single track railways.

In systems of this character it is the practice to govern the operation of the track switches and. the clearing of the signals in accordance with traflic conditions by a system of trackway circuits controlled by track relays, upon which manual control is superimposed by the operation of a suitable communication system, usually of the code type. Since train movements over the single track are permissible in only one direction at a time, the signals for both directions are usually controlled over the same circuits. This is made possible by the provision of means for setting up the desired direction of traffic through the various blocks and for clearing the signals in accordance with the condition of the blocks by the transmission of suitable codes of impulses from the point of control, which usually s the train dispatchers oilice. In the event of an accident to the communication system of such a nature as to render it inoperative, it is ordinarily necessary to operate trains by a system of train orders and to either take the signal sys tem entirely out of service or to provide local operators at the way stations.

The principal object of my invention is to provide emergency means for restoring the signal system to service under the condition mentioned, by converting it to an automatic block system of the absolute permissive type, in which the signals normally stand at clear for both directions. This is accomplished by the provision of manual switching means, comprising a two-way multiple contact switch or circuit connector at each signal location, by which all the circuit changes required at a location for conversion from centralized control to automatic block operation may be made at one time without error.

Under centralized operation but one pair of line wires are required for the control of the signals governing trafiic through the single track blocks, since the circuits are energized in only one direction at a time. Under automatic block operation an additional line circuit is needed to provide circuits for both directions, and this is obtained in accordance with my invention by using the line wires of the code communication system which otherwise would be idle. A feature of my invention is the provision of means for extending the control limits of the signals by means of the adjustable connectors mentioned to provide the proper protection for opposing 2 train movements under automatic block operation, in which longer blocks are necessary than under centralized operation in which the signals for one direction or the other stand normally at stop.

Under automatic signal operation, circuits for the power operated track switches of the centralized traffic control system are arranged in such a manner as to adapt the switches to hand operation, dual control power switch machines being provided as is the practice in centralized traffic control systems. A feature of my invention is the provision of time locking means for controlling the signals governing movements out of the side tracks under automatic operation employing apparatus which operates in a difierent manner under centralized operation.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

Referring to the accompanying drawings, Figs. 1A, 1B and 1C when arranged side by side with Fig. 1A at the left, show the track plan for the single track block extending between two passing sidings, together with the trackway circuits for one form of apparatus embodying my invention. More particularly, Figs. 1A and 10 show the apparatus at the two field stations of the centralized traffic control system located at the opposite ends of the single track block, including circuits for the control of the power operated track switches IW and TW, respectively, and for the associated entering and leaving head block signals. These signals are identified by the reference characters 2 and 8, respectively, with a sufiix R. or L designating the right-hand or lefthand direction and an additional suffix A when the signal governs main line train movements or the suffix B when the signal governs movements into or out of the siding. Fig. 1B shows the circuits for a pair of intermediate signals 3 and 4 and also for a second pair 5 and 6 at spaced locations within the single track stretch.

It is to be understood that the system is made up of unit portions similar to those shown. The circuits extending to the right-hand margin of Fig. 16 match those extending to the left-hand margin of Fig. 1A so that Figs. 1C and 1A, with Fig. 10 at the left, together illustrate the circuits for the signals governing movements over the main track of the double track stretch including the siding.

Similar reference characters refer to similar parts in, each of the views.

The centralized traflic' control system to which my invention is applied is generally similar to that disclosed in a pending application for Letters Patent of the United States, Serial No. 501,254, filed September 4, 1943, by Henry S. Young, for Railway traflic controlling apparatus. A detailed consideration or the communication system by which the system is manually governed from a central office is not needed for an understanding of my invention, and it is deemed suflicient to point out that this is of the general type shown in Letters Patent of the United States No. 2,197,130, issued April 16, 1940, to Lloyd V. Lewis, for Remote controlling apparatus, and comprises a plurality of coding units at acontrol office, not shown, and one at each field station as indicated by the reference characters U! and U2 in Figs; 1A and 1C. The oflice and station coding units are connected by a circuit including a pair of line wires Y1 and 21 which extend from the office through each station in turn over which indication codes are transmitted in response to changes in trackway conditions to indicate the condition of the s'tation apparatus at the oiiic'e. Control codes are also transmitted by the olfice coding unit at times over the same line Wires by eans of which the operator at the control office is enabled to operate a group of control relays at a selected station to impose manual control upon the trackway apparatus. As shown in Fig. 1A, the code controlled relays include a switch con trol relay IWS for governing a power switch machine ISM for the track switch IW, two signal control relays ZRHS and ELI-IS for controlling a left or right-hand signal selected in accordance with the position of switch 1W, and a traffic direction control relay ZRFS. It is to be understood that each of these relays is of the polar stick type and is operable to close its left-hand or right-hand contacts in response to a code received from the ofiic'e by the coding unit Ill.

The station shown in Fig. lC includes a similar group of control relays 7W5, SLHS, BRHS and BLFS, which are controlled by the coding unit U2. The trafiic relays ZRFS and 8LFS jointly control the direction of energization of a two wire reversible line circuit system which extends the length of the single trackblock, by means of which the signals are controlled in accordance with trafiic conditions as manifested by track relays, continuous track circuits being provided as shown. H s

As disclosed herein, the switching arrangements embodying my invention comprise groups of adjustable connectors such as the connectors H to 29, inclusive, in Fig. 1A and connectors 3| to 40, inclusive, in Fig. 113, Each connector consists of three spaced terminal posts and an adjustable copper strap by means of which each middle post may be connected either to its right-hand post, as shown, for normal centralized operation, or to its left-hand post, for emergency operation. All of the connector straps or a group are permanently connected together by means of a strip of insulating material as indicated in order to facilitate changing all of the connectors at one time without error.

It will be seen that th'econnectorstraps l I and E2 in Fig. 1A, straps 31 and '32 at the location of signals 3 and 4 in Fig. 1B, straps 51 and '52 at the location of signals "5 and-6 in Fig. 1B, and straps H and 12 in Fig. 1C are normally connected in series with the line wires Y1 and Z1 of the communication system to provide a'thro'u h linecircuit for the coding units U, which circuit'extends through each field station to the control oihce, as already pointed out.

In describing my invention I shall first explain the operation of the line circuit system under normal conditions with the connector straps all in their right=hand positions as shown, and I shall then describe the line circuits as they are arranged under the emergency condition when the connector straps occupy their left-hand positions, and finally,- I shall trace the local circuits for controlling the signals and track switches at the head block locations under the two conditions.

Under centralized operation, the two traffic relays 'ZIt-FS and SLFS at the opposite ends of the single track block are operated to similar positions by codes transmitted from the control ofiice and selectively receivedby the coding units UI and U2, and as shown, the right-hand contacts of the trafi i'c relays are closed, in which case the system is set for trafiic movements from left to right and the line wires '41 and 42, 43 and 44, 45 and 46 are each energized by connections to the terminals B and C or suitable local sources of current,

If sections 6T, IT and 8T are unoccupied, the current supplied to the line wires 4! and 42 ener'gizes a polarised line relay GHD, controlling signal '6; Fig. 1B, the circuit being completed through relay 6H1) over connectors 54 and 51, back contacts a and b of the similar relay -5HD for signal 5, back contacts I) and d of a directional stick relay 5S associatedwith relay 'SHD, connector 5B, the winding of an approach relay 5AR, contactsa and b of the track relay GTR for section 6T; line wires 14 i and 42, contacts a and b of the track relay 8TB; connectors M and 75, the right hand contacts (1, and b of relay BLFS, contact b of an approach locking relay SLAS controlled-by the opposing signals tLA and BLB, con tacts o and b of a pole changer relay BRPC controlled by signal ERA, and thence to terminal C, and to terminal -13 'at contact a of relay 'ITP through the winding of an approach relay BEAR, relay 'iTP being a repeater of the track relay 1TB for the switch section IT.

The head'blockjsignals such as the signals ZRA, 2RB-,;8RA and one, or 211A, 2LB, '8LA and 8LB, are of the well-knownsarchlight type each having a mechanism including a lamp and a circuit controller as shOWYl in Figs. 1A and 3A. When the si nal lamp "is lighted the signed displays a red or stop indication if dee'ne'r'g'iz'ecl, and displays a yellow caution or a green proceed indication when energized -in one direction or the other as indicated bythe letters G and Y on the drawing. The intermediate signals of Fig. 1B are of the color light type having three lamps for displaying corresponding indications as indicated by the letters G, Y and R, the lamps bein controlled over the contacts ("1 and e of the associated line relay HD.

The polarity of the current supplied over line wires '4! and 42 is normally such as to condition signal '6 toindicate caution, but when signal BRA in advance indicates proceed, relay SRPC becdmesenergi'zed to reverse the polarity of the current supplied torela'ytI-ID to cause signal 6 to indicate proceed. H I

The signals are normally dark,- aild as shown typically by the lighting circuit for signal 5 or for signals -8R[A "and SRB, for example, an approach relay's'iich as relay EAR or relay 8RAR. connected in series in the line circuit includingwire's 4! and 4-2 releases when the block section in approach to the signal is occupied, and relay BRAR releases a repeating relayBRAP. Relay 'S'AR, by closing its back contact or causes the lamp of signal 5 to become lighted, and the closing of back contacts a and b of relay SRAP causes the lamps of signals BRA and 8R3 to become lighted.

When relay liHD is energized, its front contacts a and I) connect terminals B and C of the adjacent local source of current to the right-hand end of the circuit including the line wires 43 and 44, over which the similar line relay 4I-ID for signal 4 is energized, provided sections 4T, ET and BT are unoccupied. This circuit extends from the terminals of relay 4I-ID over connectors 39 and 40, back contacts a and b of relay 3H1), back contacts b and d of relay 3S, connector 38 and the winding of relay SAR, contacts a and b of relay 4TB, line wires 43 and 45, contacts a and b of relay 5TB, the winding of relay EAR and connector 59, back contacts I) and d of relay 68, front contacts a and b of relay (ii-ID to terminal C, and to terminal B at front contact of relay 6TB, the polarity being such as to cause signal 4 to indicate proceed when relay SHD is energized.

Each intermediate signal is provided with a directional relay such as the relay (is. When relay EHD is energized, the release of relay TB by a train moving from left to right and approaching signal. 6 completes a circuit at back contact 0 of relay 5TH to pick up relay 6S. Relay BHD is released by relay 6TB, when the train enters section 6T, completing a stick circuit for relay (is extending to terminal B at back contact 0 of relay GHD. Then when the train vacates section 6T, current is supplied from terminals 0 and B to line wires 43 and 44 over front contacts b and d of relay BS and front contact 0 of relay 6TB to energize relay 4HD in the reverse direction to condition signal 4 to indicate caution.

Whe relay iHD is energized, its front contacts a and i) connect terminals B and C at connectors 33 and 35 to the right-hand end of the section of the line circuit system which includes the line wires 45 and 46. If sections 2T and 3T are vacant, current is supplied over line wires 45 and 46 to energize the line relay ZRHD, Fig. 1A, the circuit being completed through the Winding of relay ZRHD over the right-hand contacts a and b of relay ZRFS, connectors M and I5, contacts a and b of relay 2TB, line wires 45 and 33, contacts a and b of relay 3TB, the winding of relay 4AR, and connector 33, back contacts 12 and d of relay 4S, front contacts a and b of relay GHD to terminals B and C at connectors 33 and 35, the polarity of the current being such as to cause signal ZRA to indicate proceed when relay 4HD is energized and to indicate caution when relay 48 is energized, provided switch [W is normal. When switch IW is reversed, relay 2RHD energizes signal 2RB over its neutral contacts to indicate caution irrespective of the line polarity.

To set up the right to left trafi'ic direction, the relays ZRFS and BLFS are both operated to their left-hand positions by code control, thereby deenergizing the line circuits just traced and establishing others which are oppositely directed but similar and which include the same line wires. If signals ERA and ZRB are at stop and the associated approach locking relay 2RAS and relays lTP, 2TB and 3TB are energized, relay 3HD is energized over the circuit extending from its winding over connectors 34 and 37, back contacts a and b of relay 4HD, back contacts b and d of relay 45, the winding of relay AR and connector 36, contacts a and b of relay STR, line Wires 45 and 46, contacts a and b of relay 2TB, connectors i4 and I5, the left-hand contacts a and b of relay 2RFS, contact I) of an approach locking relay ZRAS, controlled by signals 2RA and 2R3, contacts a and b of the pole changer relay 2LPC for signal ZLA, to terminal C, and through relay ZLAR to terminal B at contact a of relay ITP.

Relays 5HD and BLHD have energizing circuits similar to those for relays dHD and ZRHD already traced. Th circuit for relay EHD includes line wires 43 and 44 and extends to terminal B at front contact 0 of relay 3TB, over front contact a of relay 3HD or front contact d of relay 3S, and to terminal C at front contact I) of relay 3I-ID or 38. The circuit for relay fiLHD includes the lefthand contacts a and b of relay BLFS and line wires 4! and 42, and extends to terminals B and C at connectors 53 and 55 over front contacts a and b of relay 5I-lD, or at front contacts d and b' of relay 58. As hereinafter described, when switch 7W is normal relay SLHD is supplied with current of normal polarity by relay EHD to condition signal 8LA to indicate proceed, and with current of reverse polarity by relay 5S to condition signal SLA to indicate caution. When switch '!W is reversed, relay 8LHD conditions signal BLB to indicate caution when energized by current of either polarity.

It Will be seen, therefore, that the single track block extends from the location of signal ZRA through the track sections IT to 8T, inclusive, to the location of the opposing signal SLA.

For the block including the passing siding separate line circuits are provided for the two directions for governing the movements of trains over the main track. Although track circuits are pro vided for sections [HT and UT of the passing track, these do not control the entering signals, and the control limits for signals 8RB and 2L3 which govern movements into the passing track include only the corresponding switch sections FT and IT.

Signal 8RA governing train movements over the main track is controlled by a line relay BRHD, which is normally energized over a circuit extending from its winding over contacts 0 and d of relay 9TB, line wires 59 and 50, contacts 0 and d of relay ll TR, contacts a and b of a pole changer relay ZRPC to terminal C, and when switch IW is normal, to terminal B through the winding of the approach relay ZRAR, connector l3, contact I) of relay ZLAS, controlled by signals ZLA and 21B. and contact I) of relay ITP. The control limits for signal GRA therefore normally extend to the opposing head block signal ZLA.

As hereinafter described, signal BRA is controlled over the polar contacts e and J of relay BRHD as well as over its neutral contacts a and b and is conditioned to indicate caution when the next signal ZRA in advance is at stop, and to indicate proceed when signal ZRA indicates caution or proceed. The pole changer relay ERPC is energized only wh n signal BRA indicates proceed, so that signal 6 in the rear does not indicate proceed unless signal SRA is conditioned to indicate proceed.

Under centralized operation the switch machine ISM for switch IW is operated by local power supplied over connector 21 in accordance with the position of the code controlled relay IWS, and when the switch, is mechanically locked by the switch machine in its normal or reverse position, a. switch indication relay INWP or lRWP is energized over a switch circuit controller contact N or R and a corresponding contact c or d of relay IWS and connector 28 or 29.

The relays lNWP and IRWP thus reflects the po-" 7 llrionof the track switch 1W andlof, its control relay IWS.

CWhenthe switch :IWis reversed, terminal Bis connected to the line circuit including wires 49 and 56 at the front contact of relayv IRWP, so that the control limits for signal SBA extend only to signal 23A. Under this condition signals 531A and '5, the rear of signal 211A, may be en sized to indicate caution only- .s gnal 'ZLA is controlled like s gnal SBA by a line relay ZLHD, which is normally energized ov r a circuit extending from its w nd ng ver contac s a and -b of relay l ITR, line wires or and 4g tacts a and b of relay 9TB, the pole changer contacts a and b of relay SLPC to terminal C. and through the winding of relay SLAB to terminal B at contact 0 of relay 'ERWP or over connector 13 and contacts 27 of relays SEAS and 1'I- P,

Signal "ZLA thus does not indicate proceegl one less switch I is normal and signal 18LA in adyance is conditi ned to indicate caution orproceed, and si nal 3 in the rear does not indicate proceed unl s i nal ZLAiS c ndit ned to in ioatep oeem The approach r lay ERAR in the cir u t for relay :8RHD, and the line relay ZLHD jointly con.- trol a slow release relay ZRAP to cause signal 33A to become li hted when the approach Zone comprising sections ST and l l 'I is'occilpied. Similar arrangements inv lving relays Bil- 3 and BLAP are provided for signal SLA. Si nal-3L1? r ZRB i i hted when th approach section l- 'l or IZT, espectiv l is o up ctdue to the re eas of the track relay lilTR or (2113, which has a back contact a in the circuit for the lamp for signal BLB or 2313.

C idering h w t o erat on o the syst m under the emergency condition all of the connector straps are placed in the left-hand posi. tion, it will be seen that the-line wires Y1 anal] are sectionalized at each signal location by the removal of the connectors from their ri ht-hand terminals. The line wires M, 4.3 and 45 and the corresponding sections of the line wine ,Zl now provide a System of two wire tandem connected line circuits for energizing relays iii-ID, AHD and 2RH-D to control traffic movements from left to right, while the line wires 48, All and 4:2 and the corresponding sections of the l ne wire Y! orer vide a similar system for energizing relays :3HD, 5HD and SLED to control traffic movements from right to left, all of these line relays being normally energized.

With the connector straps in their left-"hand position, the circuit for relay iii-ID extends from the left-hand terminal of its winding over con hector 54', back contact 0. of relay .55, through the Winding of relay 5A3 and over contact .a f relay TB to line wire {i i and thence over cons-l tact .a of relay 8 H t te minal Q at co nector 14, and from the right-hand terminalof itswind, ing over connector 51, line wire ,Zll, connector 12 through relay SRAR to terminal 13 at con-tact a of relay *ITP. The circuit for relay 41511) new extends from its left-hand terminal over co nector 39, back contact 0 of relay as, through the win ing o e ay SAR and ov r-contact of elay lT-R to line Wire 43 and thence oyercontaot a of relay 5TB the Winding of relay liAB to terminal C at front contact 1) of relay is or over front. contact a of relay 6RD to terminal B at the front contact 0 of relay li'I R, and from th e rightehand terminal of its winding rover icon: nector 46, line wire .Zl, ancl connector :59 to terminal B atthe front contact 0 of relay over front contact-d of relay cs or to terminal 0 ratfront contact by of relay The circuit for relay, QR'H-D'noW extends from its left-hand tern mi-nalover connector is, contacta of relay 2TB, wire 65, contact a of 5TB, and windin of relay AAR? to terminal C at front contact if) of relay lS or over front contact a of relay QHD to terminalC at-connector 33, and from the right=hand terminal of relay QRHD over connector 12, line wire .Zzl, connector 35 to terminal 13 at front contact ,(Z of relay is or over front contact b of relay AHD to terminal B at connector 35, It will he seen therefore that signal ,6 may indicate stop .or caution, signal 4 may indicate cantion when relay ES energized and may indicate proceed when Jrelay EHD is energized, and that signal 23A may indicate caution when relay llislor HDjs energized.

it is deemed unnecessary to trace the similar circuits for the opposite direction in detail, further than to point out that relay BHD is energized in the reverse direction over the circuit extending from terminal B at contact a of relay IT? t terminal .C at connector H, which circuit includes the line wires lit and Yi, and that relay 1- 3) is energized in the normal direction over the circuit extending from terminal :33 at front contact of relay 3TB to terminal 0 at front contact 1b. of relay Which circuit includes the line wires 44 and Y], while relay 8LHD is eners zed in the reverse direction over the circuit extending from terminal :13 at front contact d of relay is or at connector 55 over front contact 1b of relay 'to terminal C at front contact b of relay 153 or .atcon e or 53, wh h circuit i cludes line Wires :41! and Yl.

Connectors it 55025, in IA, and connectors 16 to 85, in Fig. 1.6, in the left-hand position, complete circuits which permit signals ZRA and 214A, or signals ERB and "ELB :to indicate caution attthe same time.

Under the emergency condition it might happen that two opposing trains would pass the signals rand :ELA at the opposite ends of the single track block at precisely the same time, and it is therefore necessary to :insure the provision of adequate stopping distances for both trains. in conventional single track automatic block signaling systems in which the signals stand normally at clear, this is attained 'by the proyisionof .sufiicient distance to stop both trains after they have come into view of the intermediate signals l and ,5, hath of which will indicate stop, but in the centralized trailic control sysem as hown normally but one direction is se p te 'conseoucnztly this provision is not neeglegl :and the distance may be insufficient. hati to can un er cent a d era n th st n hetn'e n si nals '3 and may be less than hat neon ed for aut mat c blo k oper ion. In sho hl clsatherei r con ctor such a a d -5 are p o ided a torljmi-t the indie trons of the head block signals to stop and caut on, While in t longer bl s hes connect rs may he omitted and the sisials rran d to rovi e the mea three indicati n nd r a tom tic n ions ons dering loci; com -rising the n trad; h 1 nhle s tch, h n t e c n- :a in the la and p si i n, lay :Z izes o er thecircu t extend n f om a centae 1 oi re ay T over contact 1: f the track re ay 5TB fo the a pr ach s t and rinie tor 5 con ac 5 of th app c ek c r lay AS bein ex l ded from th cirru t, and elay flEtHD is ner i ed o r a sim a 9 circuit including contacts I) of relay ITP and contact of the track relay ZTR for the approach section 2T, and connector I3, contact I) of relay ZLAS being excluded. The enterin signals 8RA and ZLA may both be cleared at the same time, in response to the energization of their respective line relays 8RHD and 2LHD, to indicate caution or proceed dependent upon the condition of the pole changer relays 'IRPC and SLPC controlled by the leaving signals ZRA and BLA. By placing Fig. 13 at the right of Fig. 1A, it will be seen that signal 3 governing trains approaching the passing tracks from the right stands at caution and that contacts a and b of relay ZLPC and contact b of relay 2RAS are now excluded from the circuit for relay ill-ID. By placing Fig. 13 at the left of Fig. 1C, it will be seen that signal 6 governing trains approaching the passing tracks from the left also stands at caution and that contacts a and b of relay 8RPC and contact I) of relay SLAS are now excluded from the circuit for relay BHD, Thus under automatic block operation, signals 3 and 6 may be arranged so that both indicate caution when the block is vacant, as is desirable if its length is insufllcient to provide adequate stopping distances for opposing high speed trains, as in the case of the opposin signals ZRA and ALA hereinbefore discussed, where the situation is similar.

It has been pointed out that under centralized operation relay BRPC is controlled to cause signal 6 to indicate proceed only when the next signal BRA in advance is conditioned to indicate proceed, that is to say, only when the second signal ZRA at the right is conditioned to indicate caution Or proceed and the opposing signal 3 stands at stop. Similarly, relay ZLPC is controlled by the signal mechanism ZLAG so that signal 3 indicates proceed only when the second signal BLA to the left is conditioned to indicate caution or proceed and the opposing signal 6 stands at stop. It follows that the stopping distances are provided for trains approaching a passing siding at the same time from opposite directions under automatic block operation equivalent to those provided under centralized operation.

The operation of the local circuits for the head block signals by means of which under centralized operation these signals are interlocked one with another and with the power operated track switches, will now be described; assuming first that the left to right trafiic direction is set up with the track switches IW and TW normal, with the track unoccupied, as shown, and that the central office operator has reversed the signal control relay ZRHS for clearing signal 2RA, it being understood that all of the connectors are in their right-hand position as shown.

As shown in Fig. 1A, the approach locking relay ZRAS is normally energized over a stick circuit extending from terminal B either at the nor mal contact a of relay ZRHS or the reverse con tact a of relay ZRI-IS and back contact b of route relay ZHSP, and thence over front contact a of a signal indication relay ZRGP and the contact a and winding of relay ZRAS to terminal C. The approach locking relay ZLAS is normally energized over a similar stick circuit extending to terminal B at contact a of the signal control relay 2LHS.

If a route is available, relays 2RHD, ITP and INWP are energized, so that the route relay ZHSP picks up in response to the reversal of relay ZRHS over a circuit extending from terminal B at the normal contact 0 of relay ZLHS over contacts 0 of relays 2RHS and ZRHD, contact at of relay ITP, contacts 6 of relays IRWP and INWP, through relay ZHSP to terminal C. Relay ZI-ISP releases relay 2RAS and completes a circuit for mechanism ZRAG extending from terminal B at the reverse contact a of relay ZRHS over front contact b of relay ZHSP, front contact 0 of relay 2LAS, connector 2!, contact 0 of relay ITP, connector l1, back contact a of a time element relay ITE, back contact 0 of relay ZRAS, connector l6, front contacts a of relays ZRHD and lNWP, through mechanism 2RAG over the normal polar contacts 6 and f of relay ZRHD, back contact a of relay IRWP, front contact b of relay ZRHD, the reverse contact b of relay 2RHS to terminal C of the normal contact b of relay 2LHS, thereby energizing mechanism ZRAG in the normal direction to cause signal ZRA to indicate proceed, its signal lamp being lighted by the release o-f relay ZRAP by relays ELI-ID and ZRAR when an approaching train occupies section 9']? or HT. It will be seen that the energization of mechanism ZRAG is dependent upon that of relays ZLAS and ZLGP, which check that relay 2LPC is released and that the opposing signal mechanisms 2LAG and ZLBG are at stop, and is also dependent upon the release of relay ZRAS, which relay holds the opposing signals at stop by opening its front contacts I) and c and locks switch lW by opening its contacts e and f in the circuit for the switch machine ISM, while contact a of the time element relay ITE in the sisnal circuit checks that this relay is fully released.

Relay lTE provides time locking protection against a change in route after a signal has been cleared and accepted by a train, by holding relay 2RAS released for a suitable time interval after the signal is manually restored to stop. When signal ZRAor ZRB is cleared. its indication relay ZRGP is released by the circuit controller actuated by the signal mechanism, thereby holding relay ZRAS released until the signal is restored to stop. When a' train passes the signal and enters section IT, the signal is put to stop automatically by the opening of contact 0 of relay ITP in the circuit for the signal mechanism, and the control relay ZRHS is then restored to normal by means not shown. In this case relay ZRAS picks up at once over a pickup circuit including contacts a of relays ZRHS and ZRGP and back contact b of relay I TP. If the signal is restored manually to stop bythe operation of relay ZRHS when section IT is unoccupied, relay ITE is energized over the circuit from terminal B at the normal contact a of relay ZRI-IS which includes back contact a of relay ZRAS and the front contact 6 of relay ITP, and relay ITE closes its contact 0 to pick up relay 2RAS at the end of a suitable time interval which is usually from 2 to 6 minutes. The route relay 2HSP is controlled over a circuit which being similar to the one over which the signal mechanism is controlled, serves to prevent the release of relay ZRAS to render the time locking efiective in the event that relay ZRHS has been restored to normal because a route is not available.

In case relay ZRHS is reversed when switch IW stands reversed, with relays 2RI-ID, lTP and IRWP energized, mechanism ZRBG may be energized in place of mechanism ZRAG to cause signal ZRB to indicate caution over a circuit exnow in its released position the circuit extends over connector 21 through mechanism ZRBG and over'front contact a of relay QRWP, and-contacts?) of relays 2RHD, ZRHSand ELH-S to terminal C.

Considering now the circuits for the oPD s signals, if relay ZIJHS is reversed when switch 'IW is normal and relays ZLHD, PI? and lNWP are energized, relay Zl-ISP-is energized by relay EZLHS and releases relay ZLAS, thereby opening the circuits for the opposingsignals and for switch machine 13M and energizing mechanism 'ZLAG to condition signal ZLA to indicate caution over a circuit which may be traced from the reverse contact a of relay vZLI-IS overrront contact a of relay 2HSP, connector l8; front contact of relay ERAS, back contact a of relay1TE,'connector l1, contact c of relay lTP, connector 215, back contact 0 of relay i2L'A-S, connector t8, front contact I) of relay lNW-P, contacts a and ,f of relay ZLHD, mechanism '2LAG, contacts e and d of relay ZLHD, back contact b of relay IRWP igterminal "C over contacts'b'of relays 2LHS and If the operator reverses relay .ZLHS when switch WV stands reversed with relay 1'1? and 'IRWP energized, mechanism IZLBG will. be energized in place of mechanism ZLAG, to cause si nal 2LB to indicate caution over the branch nircuit extending fromback contactb of relay lNWP through mechanism "ZLBG to front contact I: of relay IRWP, as will be apparent from the .rlracmg.

The switch machine ISM is of the dualcontrol type provided with a selector lever Hlwhich in one position conditions the switch for power operation under control of relay IWS in which position a contact DS is closed to supply current from terminal B over a switch circuit controller contact N or R, con-tact c or d of relay [WS,

and connector 28 or '25 to energize th xnmmal or reverse switch indication relay lNWPor iRWP. In a second position the selector lever Illconditions the switch for hand operation by means not show-n, in which position contact DS' is open so that relays INWP and l-RWP are deem gized. Under centralized operation, therefore, the signal circuits are opened "by relays lN-WP and IRWP so that the signals stand at stop when the switch is conditioned for hand operation, as is desirable because the switch is operated by hand principally for local switching.

I shall now describe the'local-circui-ts "efiective under the emergency condition, assuming that the connector straps occupy their left-hand positions. Connector 2'! now disconnects terminal B from the circuit for supplying power to the switch machine ISM and connects terminal '13 directly to the circuits for relays INWP and I'RWP, while connectors '28 and 28 bridge the contacts c and d of relay IWS in the indication relay'circuits, so that relay INWP or ERWP is energized and indicatesthe position of the switch as reflected by'contacts 'N and R,irrespective of the position of relay lWS or of lever Iii, so as to enable the signals to be cleared even though thetrack switch is conditioned for hand operation. Furthermore, under the emergency condition the signal mechanisms ZRAG and ZLAG may both be energized at the same time in response to the energization of their respectiveline relays when switch 12 IW is normal, and mechanisms ZRB'G and ZLBG ma be. both energized at the same time when switch lW is reversed.

When the connector straps are in the lefthand position terminal B at connector 2i supplies current over contact c of relay VIP to conhector H and thence to connectors IE3. and lid. Mechanism ZRAG is energized over connector l6, front contacts a of relays ZRHD and iNWP, and contacts e and f of relay ERHD, and over back contact a of relay IRWP and front contact I) of relay ZRFD as already traced, and thence to terminal C at connector 26, so that signal ERA may be cleared automatically regardless of the positions of relays ZRI-IS and ERAS, or of relays ZLAS and EL-AS governed by the opposing signals. Mechanism ZRAG when energized releases relay ZRGP, which in turn releases relay ZRAS.

The circuit for mechanism ZLAG extends from connector 18 over front contact I) of relay [NWP and includes contacts a, ct, e and 1. of relay field-ID and back contact I: of relay lRWP, and extends to terminal C at connector 23. If switch I'W is reversed, relay lRWP is energized and mechanism QLBG is energized over the branch circuit including front contact b of relay lRWP and back contact b of relay iNWP. .It "follows that signal: 211A or 2L5 may be cleared regardless of the position of relays ELHS or ELAS, or of relays ERAS and ERAS.

The circuit for mechanism ZRBGis differently arranged so as to provide time locking protection for movements out of the side track in accordance with a feature of my invention. When the connectors are in the left-hand positioninlay ZRAS is controlled by mechanism. ZRAG only, due to the connections from terminal B at connectors 22 and 25 to the circuits for relays ZRGP and ERAS. The circuit for mechanism ZRBGnow extends from terminal B at connector 2i over contact 0 of relay iii? to connectors l"! and f5 and thence over front Contact a of relay ZRHD, back contact a of relay INWP, connector i9, front contact 0 of relay ERAS, back contact a of relay ITE, connector 2i], mechanism ZRBG,

front contact a of relay lRWP, front contact 12 of relay ZRHD to terminal C at connector 2A. When the connectors are in their left-hand position, with signals ZRA and 2LA energized, if switch 1W is operated by hand to the reverse position for a movement out of the side track, relay INWP releases, restoring signals ZRA and ZLA to stop, but relay ZRAS remains released for the duration of the time looking period imposed by relay lTE. Relay ZRGP becomes encrg'ized over connector 25 and the circuit controller for mechanism ZRAG when signal ERA returns to its stop position, completing a circuit from terminal B at connector 22 over front contact a of relay ZRGP and back contact oof relay ZRAS and contact e of relay I'll to energize the time element ITE. The branch of the circuit for relay ITE which includes back contact a of relay 'ZLAS is now open at connector 2'5, and consequently is ineffective. Relay ITE energizes relay ERAS after the lapse of a suitable time interval, which relay is then held energized over its stick circuit and releases relay ITE. The closing of back contact a of relay ITE and of front contact 0 of relay ERAS completes the circuit for mechanism ZRBG. Th display of a cantion indication by signal ZRB is thereby delayed following the reversal of switch IW, for a time sufficient to enable a train approaching signal ZRA either to stop before passing thesignal'if its speed is low, or to enter section IT and there-' by prevent the clearing of signal 2R3 if its speed is high.

Referring now to Fig. 10, it will be seen that the circuits for signals SLA and 8LB are similar to those for signals ZRA and 2RB, while those for signals SBA and 8R3 are similar to those for signals 2LA and 2L3 described above, and that the connector straps ll to 89, inclusive, correspond in function to the straps l l to 29, inclusive. A detailed explanation of these circuits is therefore deemed unnecessary.

Although I have herein shown and described only one form of railway traific controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

1. In a centralized tramc controlling syste for railroads, a stretch of single track railway comprising a traiiic block, signals for governing traffic movements in opposite directions into said block, a system of reversible line circuits employing two line wires for controlling said signals in accordance with traffic conditions in said block, a code communication system employing two other line wires for controlling the direction of energization of said line circuit system and for selectively controlling said signals, a system of adjustable connectors at each signal location which in one position are included in said line circuits, and means including said connectors in a second position for establishing other line circuits for automatically clearing the signals for both directions at the same time in accordance with traflic conditions each of said other line circuits including one or the other of the line wires of said communication system and one or the other of the line Wires of said reversible line circuit system.

2. In a centralized tramc controlling system for railroads, a stretch of single track railway comprising a trafiic block, signals for governing traffic movements in opposite directions into said block, a system of reversible line circuits employing two line wires for controlling said signals in accordance with trafic conditions in said block, a code communication system employing two other line wires for controlling the direction of energization of said line circuit system and for selectively controlling said signals, a system of adjustable connectors at each signal location which in one position are included in said line circuits, means including said connectors in a second position for establishing a four wire line circuit system employing the two line wires of said reversible line circuit system and the two line wires of said communication system, and means including said four wire line circuit system for automatically clearing the signals for both directions at the same time in accordance with traific conditions in said stretch.

3. In a centralized traflic control system for railroads, a stretch of single track railway comprising a trafiic block, head block signals adapted to indicate proceed or caution for governing traffic movements into said block, intermediate signals for governing trafiic movements at spaced locations within the block, a system of tandem connected polarized line circuits controlled in accordance with trafiic conditions in said block for controlling said signals, means including manually adjustable connectors at'each' signal location which in one position render said circuits effective to energize the signals for only one direction at a time and in a second position render the circuits effective to energize the signals for both directions at the same time, and means including the connectors at intermediate locations in their second position for reversing the polarity of the current supplied to the line circuits for the head block signals to prevent either head block signal from indicating proceed when both are energized.

4. In combination with a stretch of railway track, a switch section in said stretch including a power operated track switch, signals for governing trafiic movements into said switch section in opposite directions, line relays for controlling said signals in accordance with traffic conditions in said stretch, manually controllable signal control relays for controlling the clearing of the signals, a manually controllable switch control relay for controlling the track switch, approach locking relays controlled by the signals each of which in one position is normally effective to prevent the clearing of the associated signal and in another position to prevent the operation of the track switch or the clearing of an opposing signal, indication relays controlled by the track switch arranged to be energized normally only when the switch occupies a position corresponding to that of its control relay, a group of manually adjustable connectors, circuits established by said connectors in either of two positions for controlling said signals in accordance with the condition of their line relays and of said switch indication relays, the circuits established by said connectors in one position only bein dependent upon the condition of said signal control relays and of said approach locking relays, and means including said connectors in said second position for rendering the energization of the switch indication relays dependent upon the position of the track switch irrespective of the condition of said switch control relay.

5. In combination with a stretch of railway track including a track switch, indication relays for indicating the position of the switch, signals for governing traflio movements over the switch, energizing circuits for the signals including front contacts of said indication relays and a manually controllable contact and also including contacts reflectin traffic conditions in the stretch, a manually controllable switch control relay, a dual-control switch machine having a selector lever which in one position conditions the track switch for power operation by its control relay and in a second position conditions the switch for hand operation, circuits for selectively energizing said indication relays including contacts indicating the position of the switch and contacts closed by the switch control relay in a position corresponding to that of the track switch, said circuits also including a contact closed by the selector lever in said one position, a group of adjustable connectors included in the circuits for said signals and for said indication relays, and means including said connectors for rendering said control relays ineffective to control the switch and signals and for completing circuits for energizing said indication relay in accordance with the position of the track switch regardless of the position of the switch control relay or of said selector lever.

6. In combination with a stretch of railway track including a track switch, a first and a second signal for governing trafiic movements in a. trailing. direction over the switch in its norma'} and reverse positions, respectively, energizingi circuits for said signals controlled in accordance with trafiic conditions in the stretch and the positionof the" track switch, an approach looking relay; a dual control switch machine having sselector lever which in one position conditions the switch for power operation and in a second to stop, a circuit for efiecting the power operation-of said switch machine including one of said connectors and a front contact of said approach locking. relay and arranged to be supplied with 16 current only when the connectors are in said one position, and means including said connectors in a second position for including a front contact of said approach locking relay in the energizing circuit for said second signal.

' THOMAS W. HAYS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Nae Date 2,176,273 Ott Oct. 17, 1939 1,805,531 Stoltz May. 19, 1942 2,298,806 Pelikan Oct. 13, 1942 1,956,605 Willard May 1, 1934 2,018,765 Preston et a1. Oct. 29, 1935 2,060,485 Bell 1 Nov. 10,- 1936 2,060,487 Vanhorn Nov. 10, 1936 2,063,971 Young et a1 Dec. 15', 1936 2,082,435 Wight June 1, 1937 2,169,615 Penrod Aug. 15, 1939 2,315,032 Young Mar. 30, 1943 

